


Heat Me Up (and hold me tight)

by DearRendezvous



Category: Haikyuu!!
Genre: Alpha Miya Osamu, Alpha Sakusa Kiyoomi, Alpha/Beta/Omega Dynamics, M/M, Omega Miya Atsumu, Omega Verse
Language: English
Status: In-Progress
Published: 2021-02-21
Updated: 2021-02-23
Packaged: 2021-03-18 07:07:43
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 4,312
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29605722
Author URL: https://archiveofourown.org/users/DearRendezvous/pseuds/DearRendezvous
Summary: "Miya-san?""What is it?"The unknown classmate scratches his head, looking embarrassed at what he was about to say next."Look, I know it's weird to ask, and it's not a part of my business, but why weren't you in school for the first two weeks ?"Atsumu's face heats up, "Ah, right, about that....."...Where Atsumu wonders how he was an omega when nothing happened, let alone changed, in him for a whole two months. No scent, no softening features, and especially no heats.Until the Gods decided to make it a full circle.
Relationships: Miya Atsumu/Sakusa Kiyoomi
Comments: 6
Kudos: 153





	1. Let The Realization Sink In

**Author's Note:**

> Nice to meet you!  
> This is my very first time to post a work, nevertheless write, a fan fiction dedicated to our beautiful nation of SakuAtsu!!! This was only managed to be created because Potato was supposed to just turn this into a mini prompt au for our beloved SakuAtsu content provider, eatsumus. Well, this happened...
> 
> Anyways, hope you enjoy~  
> -Potato

**Summary for the Chapter:**

> A change that Atsumu was least expecting, since he didn't expect that it would ever happen. But then again, Atsumu has always proudly charged head-on to whatever hindrance went on his way.
> 
> So how will Atsumu achieve encountering his first ever heat?

_**CHAPTER EDITED** _

It was how Atsumu discovered that he was NOT a recessive omega. In fact, he's actually very fertile, which is very rare considering him being a male omega.

**_2 months ago..._ **

Him and 'Samu got tested to know their gender right after their first year graduation. To their surprise, the twins were not of the same gender, Osamu coming out as an alpha and him being an omega. They were deeply educated by the doctors after the results on what to do in their heats, ruts, etc.

For the rest of the time of their school break before they turn into second years, Osamu changed. A lot.

Let's take a look at Atsumu's analysis:

The idiot actually got taller than him by at least 2 and a half inches (although Atsumu likes to argue that it's actually 2.34) and starting to gain more pounds that he can now carry his older twin like a sack of potatoes whenever the blonde attempts to steal the younger's limited edition pudding; you can say that Atsumu just gives up once he gets carried over the young alpha's shoulder like a successfully caught deer in a hunt responding that the pudding's going to get expired a few days after anyway.

His gluttony level that was on supposed to be boss level 10 turned to a 50: an exaggeration by Atsumu but it's not _TECHNICALLY_ a lie considering the glutton's food schedule used to be 4 meals of rice and then 6 snack breaks a day, now add eating meat AT 2 IN THE MORNING (let's face it, Atsumu's just mad that he wasn't invited to eat with him in the middle of the night), the dumbass is starting to smell AWFULLY strong, and by the screams of the heaven above and the hell below, 'Samu's starting to care about his appearance! Since when? Apparently, now he does.

And Atsumu?

Nothing.

For two whole months outside of school nothing MUCH changed. Sure, he can smell things better than before and he gets maybe a little more sensitive than before, but that's about it. Although that event seemed to please the twins parents. They were both betas so they don't know how to deal with the occurrences that happened to alphas and omegas that they can feel on a personal level. Well Atsumu can't complain since he saw the shocked faces of his and Osamu's parents when the doctor explained what will Atsumu experience now that he's an omega. About the physical changing, change of mental thinking, and THE HEATS.

The Miya family is relieved that nothing happened to Atsumu. Except for Atsumu.

Even as an omega, Atsumu will never want to be weak nor submissive. He doesn't care if he might be a late bloomer, or his weird omega hormones are berserk that really just don't work or too weak to work. When he becomes famous, he is not gonna be known as Osamu's omega twin, no- he'll still be known as Miya Atsumu, the setter who's done impossible sets good looks.

Key word: might.

But there's just something there that talks to him deep inside his head that makes himself look at the mirror, to see if anything changed. Oh look, all of his skin blemishes are gone. Body wise? Nothing really appeared nor disappeared. Is it wrong that he feels insecure about it? Hell nah.

And so he disregards those thoughts by focusing on something else other than matching what he looks like with what his status is.

He continuously works out, the muscles on his body just getting tighter rather than widening his shape, he doesn't care.

He competes frivolously and continuously with his twin; from cooking, exercise, and volleyball, sometimes leading to full- blown arguments, words so fast spitting out of his mouth that can make Atsumu compete in national level rap battles that he just might get championship on. Despite being reprimanded of his attitude towards him mocking his brother, again, he doesn't care.

And now that a new routine has fallen on him that levels, maybe even outweigh, his new status of being omega, Atsumu is slowly accepting.

He might be recessive, okay, even though his job as an omega is to carry life might turn into a barren and unfulfilled destiny. He doesn't care.

But it seems like Mother Nature wants to fuck with him again with destiny and fate chortling by her side.

**_Present..._ **

First day of school the Miya twins are on their walk to go to school as fresh and new second years. Atsumu measly yawns as he holds onto the straps of his school bag while the big bad glutton beside him yawns and chows down on an onigiri almost as big as Atsumu's hand with fingers stretched to the max. Osamu had gotten his first rut two weeks before today, and although it only lasted four days, he stank up their whole room that Atsumu had to stay in their parents' room because the guest room hadn't been properly cleaned yet. It was as musty as an abandoned mansion.

Osamu with barely open eyes continues walking with the rice treat in hand, grains messily on his cheeks as they slowly fall to his uniform, falling off with a shrug of his broad shoulders. He was about to take a bite once more...

...if it wasn't for the fact that metal clangs on his right, startling him. He was about to give his bottle blonde twin a glare as to why and how he managed to knock himself out on a metal sign. But then he didn't.

He would have, if it wasn't for the fact that his brother collapsed and cheeks covered with fever blush, shivering like he was tossed into snow 6 inches deep in the middle of the Arctic. And he's starting to smell good. Really good.

Fuck.

Atsumu's vision blurs as he's suddenly lifted up, and bounced into the arms of his carrier like he's riding on a full sprinting race horse. He hears a door creak open, just faintly so, as he hears alarmed voices slurring in and out his ears. He doesn't dully take note as he's placed on cool sheets that somehow cool him down. He crawls deeper to the middle of the sheets, settling himself comfortably. Using the now hushed voices as a crooning lullaby, he fell asleep.

He woke up to his mother comfortably rubbing on his back, sleep slowly wearing off. His senses now on high alert as the drowsiness now completely fades from his consciousness. A slight rub on his shoulder causes him to look at her mother's face wearing a gentle expression. "We bought pillows and blankets that you need for nesting," she says as she points to the corner of the room where the items are stacked beside a mini fridge, "and we've alerted your doctor what happened."

Atsumu listens eagerly, wanting his mother to continue, to know what a professional has to say. "It's normal," with a silent sigh of relief he continues to listen, "she said it might be the fact that you were with Osamu in the womb, so being with him, his own alpha pheromones somewhat influenced yours a little bit. The reason for the sudden fever you've gotten was because your body finally removed the unwanted alpha chemicals, and the lagged behind omega hormones were finally released all throughout your body. This is the guest room, don't worry it's been cleaned three days ago, which we will give to you cause we can't let you stay with Osamu anymore, with you having your time of heats and his time of ruts. After your heat we will permanently move all your things here. Your real heat will start in two days, which the doctor estimated to last at least five days to a whole week, maybe more but she isn't sure. And about the nesting," she continues as she holds Atsumu's hands on her own, rubbing the back of it gently, sensing the quiet anxiety swimming in her son's eyes she continues.

"Just trust your instinct, it'll help you. Okay?"

And like magic, the deep doubt about to turn into tears of the omega disappeared, the waterworks going back in reverse. Atsumu's chest feels light, as he hugs his mother, nodding with his face in her chest. As a beta, she doesn't possess any scent. Yet the smell of laundry detergent from her clothes calms the omega down, letting her go as she pats his head and walks out of the room, closing the door gently on her way out.

With a sigh, Atsumu blinks his eyes and gets off the bed. walking towards the pile of nesting materials, or so his mother says, wedged in the corner of the room. The stack of materials consisted of two fluffy comforters, a dozen pillows, a few giant animal plushies, and another pair of blankets. Each and every material was scentless.

He looks away for now, walking to the direction of the mini fridge. Opening the appliance, it was full of water, juices, sugary sweets and some comforting snacks that was a mixture of rice treats like sushi and onigiri, and the store bought chips and biscuits. Ooh, there's ice cream.

Losing his patience over his own self for a moment, he closes the mini fridge. Back in front of the stacks of fluffy objects that were supposed to be what he will use to create his fluffy haven. Picking up a reversible octopus plushie, which seems to be the smallest in the pile, with a happy face on the yellow side and a cutely-made mad face on the opposite red side. He knows what to use now, and so he looks back at the pile.

_What the fuck am I supposed to do now?_


	2. Heated and Prepared

**Summary for the Chapter:**

> Whilst in the dead of the night, everybody within the residence of the Miya household is peacefully residing in slumber.  
> Except for one busying himself with all the muffled hustling and bustling inside his room.  
> .  
> .  
> .  
> Sneezing, much less getting sick, isn't really Sakusa's forte. Yet he doubts the reason of it could be anything but a cold.

**Notes for the Chapter:**

> Hiya!  
> Sorry this update took so long, I was completing school work and had a little bit of a brain lag for the past few days, so in order to make up for that this chapter is twice longer than the previous one!  
> If there are any errors on my grammar and spelling, forgive me because English isn't my first language.  
> Hope you enjoy this update~!!!  
> -Potato

**_2 days later,_ **

**_Wednesday, 8:02 p.m._ **

**_Miya Residence..._ **

You know, Atsumu didn't really expect to wake up in the middle of the night. Considering he fell deep to sleep when his head hit the fluffy cushions of his pillows two hours ago right when they finished dinner. Positioned as a starfish in his bed, he looks to the left to see the untouched mountain of plush and caress-able clouds. Well, save for the bipolar stuffed sea alien on top of his study desk.

Since his heat hasn't arrived yet, their parents decided to move his wardrobe and desk right inside so that there will only be a few minorities left in Osamu's to-be lonely room. it's gonna be something they're gonna have to get used to, it's weird to fall asleep alone, especially when you get used to feeling the weight of someone snoring right above you. It's gonna be lonely, although none of the twins would ever admit to it.

With nothing to do, he got out of bed and went to the cooling appliance on the other side of his room. All that thinking made him hungry.

He's been eating just like 'Samu ~~the pig~~ for the past two days. Bottled water on one hand and a box of pocky on another, he went to sit in the desk located right next to his bedroom door. He'd rather not have ants crawling with him if he ever decides to eat on his bed, as much as he wants to he'd rather be the twin more different and hygienic than his boar of a brother if he's gonna be staying here from now on. A stick of pocky in his mouth, he remembers what the doctor told him over the phone.

* * *

**_Flashback..._ **

> _"Atsumu, you are about to experience heat and even though we've already talked about it I need to tell you more things that I haven't explained in full detail. I'm telling you this because you are the one experiencing it, you're parents don't need to be aware of it due to the fact that this will now be a regular occurrence after your first heat. You're nesting is not something that you must be worried about, alright?"_
> 
> **_"Just trust your instincts, okay?"_ **
> 
> _Remembering his mother's words, he confirms the doctor on the other side of the phone, "Yes."_
> 
> _"Good. The first stage of your heat will only last a day, a short fever. That's your body changing and getting used to the omega hormones the brain is releasing. This may also continue up until your fifth time experiencing heat, after that your body will get used to it that it won't happen anymore because you're body got used to the transition,"_
> 
> _"The second stage is what you will experience the most duration to; Ovulation. Now this is what your heat is all about, it's the time that you're body is experiencing the most because it's the time that you are creating the most egg cells, if you copulate with an alpha during your time of heat at this stage, there is a 75- 90 percent chance of a fetus to form inside you. This may last 3-5 days of both excruciating pain and pleasure. Have you been eating like maybe twice more than regular the past few days?"_
> 
> _"I have."_
> 
> _"Good, that's because your body is physically preparing you to exhaustion so that you have energy to spend, your metabolism level is higher than before so that your body can collect much nutrients from what you eat so you won't pass out."_
> 
> _Atsumu's cheeks flush in embarrassment, "Will I really be that exhausted in my heat?"_
> 
> _The female doctor laughs, "That's for you to judge, everyone has different explanations on what happens in their heats. And we have the third and the last stage; Recuperation. You're basically gonna be asleep for the whole day, it only lasts one day and then you're gonna be good as new the next day after. So Atsumu, do you have any concerns that we should address now?"_
> 
> _Atsumu bites his lips in worry, but then blows a soft sigh as he asks, "How long will my heat last?"_
> 
> _"The average number of days that people experience heat is 5-7 days, with the ovulation period 3-5, if their body is done with the proper transitioning it turns into an ovulation period of 4- 6. I would say you might experience the week-long period with an ovulation of 5 days, but I am not certain."_
> 
> _"Not certain, why?" Atsumu questions, clearly confused on what the doctor meant._
> 
> _"Well, the development of one's second gender is 89% of most people passing through the genes. Based on your family tree, you only ever had one blood relative that had alpha blood in him, yet he is recessive. Meaning most of his alpha structure remains dormant, the rest of your family members are beta. You twins are rare, based on the check-up after Osamu's heat, he is a dominant alpha so you might be too. We will clearly know after your heat, Atsumu. Would you like to ask one more question before we drop this call?"_
> 
> _"Is...is this normal?"_
> 
> _"Atsumu, the two of you are rare in the family. Based on what I told you, clearly not. But, nothing's bad about it okay? Now, I'll end the call now, don't forget about your check-up after your heat and good luck."_
> 
> _"Okay..."_
> 
> ***doot***
> 
> * * *

Chewing the biscuit, he sits on the chair backwards as he checks out the unfamiliar room.

Right in front of him is his bed smack dab in the middle of the room, the bedroom door just a few steps away from his desk. On his right on the same wall where the desk resides, is his wardrobe closet, he remembered he had to tell his parents to put it there instead of the right side of his bed from the headboard because he feels like that wall needs something that even he himself cannot say.

So if you're sitting on the bed with your back on the headboard, the right wall is empty space, in front is the door and his study desk a little bit to the left same with his wardrobe, and on his left is the mini fridge with a window above it and the corner containing all his nesting materials.

He looks back at the bi-colored octopus plush sitting on top of his unused notebooks, then back at the pillows. Atsumu had the sudden urge to go into the mini mountain.

And so he did.

Leaving his chair and snacks on the table, he walks over the far corner of the room. As his hand makes contact with a pillow, he feels like a switch has been flipped. Without thinking, he grabs the pillows and stuffies he can fit within his arms, walks and throws it onto the empty side of his room, onto the right side by his bed. He made several travels until everything was right there.

_I think I know what to do..._

**_10:21 p.m._ **

"Oi, Tsumu! Ma said something about ya' needing thi-"

Osamu, halfway into his twin's room, stops, with his left hand on the door's knob and the other holding two pieces of clothing.

Nothing seems to be out of the ordinary.

Except for the fact that Atsumu is now laying in a nest made of fluff situated in the middle of his bed and the wall. One of the fluffy duvets above his head, only his head popping out of the hood. He was hugging a fluffy pastel grey cat face plushie that's as big as Osamu's whole torso and abdomen. With the fear of possibly being bitten by his rabid twin brother, he keeps it to himself that he actually finds Atsumu's current situation absolutely adorable bizarre.

Cute.

He steps closer, closing the door silently as he fully goes in and not continuing hanging in the doorway. The blonde still doesn't seem to notice him though, eyes blank of emotion save for the fact that his pupils are largely dilated that only a ring of his warm honey eyes sparkled with cocoa can be seen. The omega is also (oddly) quiet, nothing but little breathes coming out of his mouth paired with flushed bright cheeks. Just what is this guy thinking about? Before that thought could turn into a whole overthinking process, Osamu gasped. It was faint, but it's there...

Oh.

A little rumbling sound interrupting the silence in the air, like a sound that a domestic feline would emit when satiated and high on serotonin.

_Oh._

Purring.

_Atsumu is freaking purring..._

And that's when Osamu decided he has to take a video of the current state that his doppelganger is in, and send it to the walking blackmail chamber known as Suna Rintarou, Osamu wonders if he can trade this for a few cups of pudding. With his objective done, he puts his phone back to his pocket and uses a hand to shake his brother out of his prolonging stupor.

"Oi, done being a scrub yet?"

With his twin brother's jest, Atsumu quickly flares up as his brain tries to find a witty comeback that would absolutely push the silver head's buttons that would result in them having a full on brawl in his brother's room-

Except for the fact, that instead of that happening, that was not what happened.

The blonde's hazy eyes disappeared, with his head turning to look at the intruder. No words of question except for one of the blonde's eyebrows to arch up, the action itself was asking Osamu why's he in here for.

Shoving the two pieces of heavily scented clothing to the omega's chest, the younger twin replies, "Ma said something about you needing this for your nest or somethin', so I welcomed myself in-"

"You **barged** in here," Atsumu swiftly corrected.

With a roll of the blonde's eyes and the waving of the other's hand as if to dismiss the interruption, he continues. "Yeah yeah, and I found ya here looking at the wall like it's a renaissance painting from the 1800's. There's that, and I should probably leave now."

The young alpha quickly leaves before Atsumu could scold him and (begrudgingly) thank him for the heavily scented sweaters. The blonde looks down, takes one of them, and inhales.

Smells like fall.

The smell of burning wood, sorta like campfire, was the most prominent. With his incoming heat enhancing his senses, Atsumu can also smell the barely there mint of probably Osamu’s toothpaste.

His parents were betas so they have no self-scented clothes to offer to the omega, but they’re parents made do with his mother spraying an old clean shirt with her perfume that she frequently uses and one of his father’s necktie covered by the smell of his deodorant.

Atsumu lays down, covered by the scents of his family around the nest as he hugs the plushie tighter. His head sinking down on the pillow, he thinks at what his scent might smell like.

He remembered the first discussion they ever had with their doctor on they’re first ever check-up.

Alphas and omegas have two different scents: one for individuality and one are their pheromones, the ones they release in time of heats and ruts.

The individuality scents are different from person to person; it can go from nature to spices and sometimes even beverages, each is unique. Exactly what it’s called, for individuality. Some working establishments use these as a recognition as to who’s an employee or etc.

The second one is what doctors describe as “Philter Scents.” It smells erotic for the purpose to attract potential partners whenever an omega is in heat and an alpha is in rut. Philter Scents can also be emitted when the omega or alpha is aroused. These odors can be somewhat similar or common, especially in families because it is hereditary, so having a different philter than your family bloodline is considered very rare.

Omegas release “Gyno Philters,” said to smell like feminine scents to attract dominant males, alphas and a scarce of beta males that are either from dominant alpha bloodline or strictly dominant beta. Most betas, which is most of the population, are recessive therefore they cannot smell omegas nor emit any individual scent.

Alphas release “Andro Philters,” in their ruts that attract omegas and females, beta and omega alike, and even recessive alpha females that are rare.

Omegas and alphas have different developments, with alphas obtaining their individual scents after their first rut and their androphilters at ages late 17 to early 18. Meanwhile, omegas first obtain their gynophilters on their first heat, specifically on the second day of their ovulation and get their individuals from ages 19- 21. 

With that in mind, Atsumu wonders if he would have the same scent as his twin, will he smell like Fall too? But Atsumu is more of a spring person, but that’s beside the point.

He rouses his head, but suddenly lies back down. He wonders what gave him a headache, did he lift his head too quickly? His heat is coming tomorrow, so that might be a reason too. Giving up on trying to get up, he lifts an arm to get his phone off the bed. With the object in his hand, he opens it.

**_11: 59 p.m._ **

_Shit…_

* * *

**_Next Day,_ **

**_Thursday, 12: 25 p.m._ **

**_Itachiyama Institute..._ **

Sakusa sneezes, scaring both him and Motoya.

“Did you just SNEEZE?!?” squawks his cousin hiding behind his chair, knowing full well how the younger is always conscious about his health. 

Taking out a tissue to wipe his nose, he glares at the brunette looking at him audaciously while slowly sits back down. 

“I’m certain you need glasses if you didn’t see that when your face was literally just a foot away from mine,” Sakusa grumbles as he continues to eat. Motoya huffs in both offense and exasperation, quite grateful actually that his cousin didn’t ~~try to attempt to~~ stab him with a pair of chopsticks. 

The younger’s mood has been all over the place since yesterday and the day before that, simply because he feels unusual.

And that’s very un-Sakusa-like, so Motoya is stuck to ask questions to a hot- tempered ravenette that is basically answered in either sarcasm or grumbling, sometimes he gets a full-course meal of both with an eye- roll for dessert.

Sakusa has been eating a lot, like at least twice than he normally used to, experiencing sudden bouts of energy that he puts into volleyball causing him to fling out untouchable serves and pain to receive spikes, not to mention that his patience level seems to be as long as an eyebrow hair nowadays.

Remembering the time when he caught Sakusa staring at the wall like it was the cause of his suffering while eating his second pack of sour gummies almost made Motoya snort the water out of his nose.

And so he receives a look of disgust by his cousin.

With the disdain that Sakusa feels at what his cousin did and all these random urges that disrupt his normal and organized life schedule, his increased foul mood activated his scent to erupt inside the classroom.

It would have been fine, except for the fact that Sakusa smells of rum.

Like how dangerous inhaling alcohol vapor is, it’s dangerous that Sakusa releases this much negative pheromones along with his heavy scent that can immediately go to one’s head. 

Unfortunately, Motoya is a dominant beta making him be able to smell Sakusa’s mood. _Literally._

_Jesus, it smells like that one time their wine room flooded but this is most intense…_

Motoya wants to curse their generation as to why they had to each smell like a different section of a liquor store. And he looks back at the younger grumbling troll, who's unaware of the pheromones he’s releasing.

_Better make him stop now before somebody calls for a teacher._

_Oh boy…_

**Notes for the Chapter:**

> Yayy, Sakusa is now introduced into the story!  
> As you can see, it was very long because I like things to be very practical and make things make sense, and I want to have a personal trademark on this book, making them have two scent for two different reasons!!!  
> Lemme know what you think!!!  
> Kudos and constructive criticism is very much appreciated, don't be shy and tell me what you think of the story so far in the comments, I would very much like to read them~!!!  
> See you next update!

**Author's Note:**

> If you've read this, then congratulations for dealing with this rookie work of mine.  
> Comments, especially constructive criticism, and kudos are very much appreciated!!!  
> Thank you for reading and see you next chapter~  
> 


End file.
